1. Field of the Invention
The present invention relates to an image sensing system, in which a plurality of cameras are communicably (hereinafter also referred to as “communicatably”) connected.
2. Description of the Related Art
In an image sensing system in which a plurality of cameras are connected through a linking device, such as a wireless LAN, for performing a collaborative operation, conventionally available is a system in which a master camera controls a release operation of a slave camera. For instance, Japanese Patent Laid-Open No. 2005-130030 discloses the following system. More specifically, a master mobile telephone transmits shooting time information to a slave mobile telephone, and the slave side executes a release operation in accordance with the received shooting time information. In this system, delay time from the moment the master side transmits a pseudo trigger signal to the slave side to the moment the master side receives an ACK signal transmitted from the slave side is regularly monitored, and the shooting time information is determined based on the delay time.
However, the system according to Japanese Patent Laid-Open No. 2005-130030 only gives consideration to the delay time, which is caused by communication between the master side and the slave side, and does not consider delay time from trigger signal reception to a start of a release operation in the slave side. For this reason, proper control cannot be performed in accordance with a type and conditions of the slave camera. Therefore, exposure timing of the master camera and the slave camera cannot strictly be controlled.
Accordingly, it has not been able to realize image shooting control, such as accurately synchronizing exposure timing of a master camera with that of a slave camera for shooting an event at the same moment from different angles. Furthermore, sophisticated control, such as performing slave camera's exposure at exact intermediate timing between an exposure end and an exposure start of a master camera's continuous shooting, cannot be realized.